Aldoe condensation product and vulcanization of caoutchouc therewith



atentiecl Apr. 15, 1930 v 1WD B. ElEBRELL, OF AKRON, OHIO, ASKHGNOB TO THE GOOD l t THE 6: RUBBER COMPANY, F AKRON, OHIO, A CORPORATJIIQN fill @HIU TA CONDENQATION PRODUCT AND VULCANIZATION till? UAQUTUHUUG THERE lto Drawing.

My invention relates to methods of vulcanizing rubber and rubber compounds, and it has, for its primary object, the provision oi accelerators of high curing power and wide a adaptability in the art.

in U. S. Patents 1,417,970 and l, l67,984 a number of reaction products having accelerating properties are disclosed, which result -from the condensation of aldehydes with amines and the further condensation of this product with more aldehyde. The present invention, however, relates to the condensation, without the loss of water, of an aldehyde to give a product which can then be easily combined with amines, to form accelerators of high curing power, and which have the added advantage of being very stable toward heat and aging. Moreover, the product may be produced without loss of volatile materials, thereby obviating the need of an expensive apparatus which would be necessary to recover such materials.

It is also an object of this invention to provide a product which may be formed by the condensation, without the loss of Water, of an aldehyde to form an aldol and by treating this material with an amine to obtaina material which, upon further treatment with an aldehyde, gives a desirable accelerators Another object of this invention is to provide a vulcanized rubber product having good aging properties, high tensile strength and which requires a short time of cure that may be prolonged, according to the .requirements of the process, without detriment to such product. v

By Way of explanation, acetaldehyde will be used as an example, but it is known that other similar substances may be used with advantage. When acetaldehyde is treated with any one of a number of substances, which have the desired catalytic eiiect, among which are zinc chloride, potassium carbonate and hydrochloric acid, an addition product is obtained without the loss of water. The reaction is represented as follows:

Aldehyde moi Application filed November 10, 1924. Serial li o. rennin.

Chemically this substance can be ltened to aldehydes and hetones. For example, it forms condcnsationproducts and gives the characteristic reactions with sodium bisulphite and hydrorylaniine, but it difi'ers in several important respects. Thus, it decomposes on heating at ordinary pressures to give dehydrated lunsaturated compounds,-

chief among which is crotanaldehyde;- this can be shown by the lollog reaction v H H n n: n wFZ:9.- on

rant Acctaldol Grotone!den idm,

Acetaldehyde does not show this crotonaldehyde reaction. Furthermore, by treating acetaldehyde with aniline,"ethylidine aniline is formed and if this material be further treated with HON, the nitrile results which can be decomposed with water to form the acid. But the aldol-aniline addition product does not show this characteristic property of V the aldehyde derivative. Thus it is evident that not-only are the starting materials different, but (as could only be expected) their reaction products are difi'erent. This is well brought out-in Ritchters Organic Chemistry,

volume 2, Translation from the 11 edition,

page 91, line 9:

omen unocin on :CH(NHG,H,) 2'

I call attention to the misprint in line 11 which mentions the nitrites of a-anilido-carboxylic acids. This, of course, should be nitriles of a-anilido-carboxylic acids, as is brought out later in line 27, which speaks of +0111!!! +HCN +1110 Aldehyde-vAlkylldenc aniline- Nitrfle of anilidw Analido carcarboxylic acid boxylic acid Aldol+Aldol-anfline No reaction No reaction From what has been said above it is evident that the chemical properties of aldol have changed considerably from those of the aldehyde from which it was formed, but the physical properties have undergone even a greater change.

In this particular case acetaldehyde is a very fluid volatile liquid (B. P. 2022 0.), having a pungent disagreeable odor, whereas aldol is a viscous non-volatile liquid (B. P. 6070 at only 12 mm. absolute pressure) without the offensive odor, and which decomposes when distilled at ordinary pressures.

The second step in my process utilizes the well-known properties of ketones, aldehydes and aldols alike, namely, that of reacting with other substances or themselves, with the elimination of water, to produce a class of materials known as condensation products. Thus, for example, aniline reacts with ac'etaldol to give acetaldol-aniline. The reaction product thus obtained is itself an excellent accelerator, but it may be made to further combine with either aldehydes, aldols or amines to give products of desirable activity.

and having properties which allow it to be easily handled in the various steps before vulcaniaztion. 4

In the same way, as above described, acetaldol will react with ammonia, 1-4-amino-meta xylene, ethylenedia-mine, ortho and paratoluidine, butylamine, diethylamine, methylaniline and other amines or mixtures thereof. A method of preparing specific condensation products embodied in my invention follows:

Example 1 Equimolecular (portions of acetaldol and aniline are mixed irectly in a flask, some heat is evolved during the resulting reaction, but

, not suflicient to volatilize the ingredients.

After the reaction has apparently completed itself, the product is allowed to remain at 100 C. for several hours, afterv which it is I subjected to steam distillation, to remove any unreacted aniline and is finally dried.

When this condensation product was added to stock having the following formula,

100 parts rubber 5 parts activator 3 parts sulfur .5 part condensation product the time required for vulcanization was found to be about thirty minutes and the product thus obtained elongated 845% at the breaking load of 164 kgs/cm.

Ewample 2 If the accelerating vmaterial, as pre ared above, be treated with one-half mol. 0 formaldehyde, and compounded in a stock, as above set forth, a minute cure gives a product which at the breaking load of 160 kgs/Cm? elongates 825% of its original length. This latter accelerator, however, has the advantage of being a solid and may, therefore, be more readily handled than a heavy semi-fluid.

Example 3 -fluid which will perform such functions may,

of course, be used in place of ether. This material when incorporated in rubber gives a cure in minutes and the product thus formed elongated 840% at the breaking load of 135 kgs/cm.

In the above tests, zinc oxide was used as an activator, but litharge or salts of lead or zinc, such as stearate, acetate, benzoate or other compounds will function in like mannor and may be used without departing from v the scope of my invention. 1

I have chosen to designate the products formed by applying the names of the ingredients used, largely because only in a few cases is the true structural formula known; furthermore, the products polymerize on standing and robabl undergo some structural change. he fo owin table gives examples of such products with t e results of the physical tests when incorporated in a' caoutchouc mix:

E1011. Load in Condensate of in per knJcm' mum. cent at O-toluldine and acetaldol 3064011. ans 150 s t e a In W P-tolnldine and meta-Idol. 15 870 170 l-4-amlno-m-xylsne aoetaldol 30 $5 160 Ethylenediamlne acetaldoL. 15 8% 180 Bcnzylamins acetaldol 46 825 1G) All '45 82) 154 N-bntylamine acotaldol 10 805 178 Ammonia acotaldoL 840 135 Aniline acetaldol so 786 130 Aldobanfllne formaldehyde acetaldoL 45 825 160 Dl ethylamlne soetaldol----- 56 800 130 Dibutylamine acetaldol 50 860 120 I have found that the addition of a small amount of a fatty acid or metallic salt thereof llll to the caoutchouc mixture materially aids the vulcanization and improves the aging properties. Another variation which may be practiced with desirable results is to combine the fatty acid with the accelerator before add ing it to the caout choucl ether there is y a chemical reaction involved in this combination is not lmown, nevertheless, the physical be made in the application of the examples oil my invention without departing irom the scope thereof and I desire therefore that only such limitations shall be imposed as are indicated in the appended claims...

What I claimis:

l. A method of vulcanizing caoutchouc that comprises has caoutchouc with a vulcanizing agent, incorporating in the minture a product formed by the reaction of an aldol with aniline, mixing an activator therewith and applying heat.

2. A vulcanized product formed by the re.- action of caoutchouc, a vulcanizing agent, an activator and the product resulting from the reaction of acetaldol with aniline,

3. The process of producing vulcanized rubber which comprises incorporating into rubber the reaction product of a primary aromatic amine having a single benzene nucleus with aldol and heating the resultant mixture with a vulcanizing agent to effect vulcanization.

4. The process of producing vulcanized rubber which comprises incorporating into rubber the reaction product of a primary aromatic amine having a single benzene nucleus with a hydroxy derivative of an aliphatic I aldehyde, and heating the resultant mixture with a vulcanizing agent to effect vulcanization.

5. The process of producing vulcanized rubber which comprises incorporating into rubber the reaction product of equimolecular proportions of aniline with an hydroxy-aldehyde, and heating the resultant mixture with a vulcanizing agent to efiect vulcanization.

6. A method of treating rubber which comprises subjecting it to vulcanization in the presence of a reaction product of acetaldol and a material selected from'a group comprising orthotoluidine, para toluidine, amino xylene, aniline and benzylamine.

7 A rubber product that has been vulcanined in the presence of a reaction product of acetaldol and a material selected from a group comprising ortho tin para toluidine, amino lene, ti t and henizyl amine. 4

In witness whereof, l have ereunto signed my name,

liUlN SEBRlllhlh, 

